 /*******************************************************************************
  * Copyright (c) 2000, 2004 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.editors.text;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.DisposeEvent;
 import org.eclipse.swt.events.DisposeListener;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.RGB;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.ColorDialog;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;

 import org.eclipse.jface.resource.JFaceResources;

 /**
  * A "button" of a certain color determined by the color picker.
  *
  * @since 2.1
  */
 class ColorEditor {
     
     /** The extent. */
     private Point fExtent;
     /** The image for the push button. */
     private Image fImage;
     /** The current RGB color value. */
     private RGB fColorValue;
     /** The current color. */
     private Color fColor;
     /** The image push button which open the color dialog. */
     private Button fButton;
     
     /**
      * Creates and returns a new color editor.
      *
      * @param parent the parent composite of this color editor
      */
     public ColorEditor(Composite parent) {
         
         fButton= new Button(parent, SWT.PUSH);
         fExtent= computeImageSize(parent);
         fImage= new Image(parent.getDisplay(), fExtent.x, fExtent.y);
         
         GC gc= new GC(fImage);
         gc.setBackground(fButton.getBackground());
         gc.fillRectangle(0, 0, fExtent.x, fExtent.y);
         gc.dispose();
         
         fButton.setImage(fImage);
         fButton.addSelectionListener(new SelectionAdapter() {
             public void widgetSelected(SelectionEvent event) {
                 ColorDialog colorDialog= new ColorDialog(fButton.getShell());
                 colorDialog.setRGB(fColorValue);
                 RGB newColor = colorDialog.open();
                 if (newColor != null) {
                     fColorValue= newColor;
                     updateColorImage();
                 }
             }
         });
         
         fButton.addDisposeListener(new DisposeListener() {
             public void widgetDisposed(DisposeEvent event) {
                 if (fImage != null) {
                     fImage.dispose();
                     fImage= null;
                 }
                 if (fColor != null) {
                     fColor.dispose();
                     fColor= null;
                 }
             }
         });
     }
     
     /**
      * Returns the current RGB color value.
      *
      * @return an rgb with the current color value
      */
     public RGB getColorValue() {
         return fColorValue;
     }
     
     /**
      * Sets the current RGB color value.
      *
      * @param rgb the new value for the rgb color value
      */
     public void setColorValue(RGB rgb) {
         fColorValue= rgb;
         updateColorImage();
     }
     
     /**
      * Returns the image push button.
      *
      * @return the button which shows the current color as image
      */
     public Button getButton() {
         return fButton;
     }
     
     /**
      * Updates the color of the button image.
      */
     protected void updateColorImage() {
         
         Display display= fButton.getDisplay();
         
         GC gc= new GC(fImage);
         gc.setForeground(display.getSystemColor(SWT.COLOR_BLACK));
         gc.drawRectangle(0, 2, fExtent.x - 1, fExtent.y - 4);
         
         if (fColor != null)
             fColor.dispose();
             
         fColor= new Color(display, fColorValue);
         gc.setBackground(fColor);
         gc.fillRectangle(1, 3, fExtent.x - 2, fExtent.y - 5);
         gc.dispose();
         
         fButton.setImage(fImage);
     }
     
     
     /**
      * Computes the size for the image.
      *
      * @param window the window on which to render the image
      * @return the point with the image size
      */
     protected Point computeImageSize(Control window) {
         GC gc= new GC(window);
         Font f= JFaceResources.getFontRegistry().get(JFaceResources.DEFAULT_FONT);
         gc.setFont(f);
         int height= gc.getFontMetrics().getHeight();
         gc.dispose();
         Point p= new Point(height * 3 - 6, height);
         return p;
     }
 }

